I think that it is important to make sure that you have skills in the right area for the job that you are applying for. It can be tempting to try everything that comes along, but it is better to make sure that you have some qualities that would help you to do that job. Then you can highlight those qualities as part of your application and it should help you to have a better chance of getting the job. If you keep applying for everything that comes along, you are likely to get bored of doing applications, loose enthusiasm and not come across so well.